ext4 journal, question about levels

Mr. Alex · 09-04-2010, 05:39 AM

There are 3 of them:
data=journal
data=ordered
data=writeback

Do I understand it correct - "writeback" provides best performance and you can lose data easily. "Journal" provides worst performance and best data protection. "Ordered" is something between them, average.

AND:
To mount ext4 is fstab in "journal" mode should I save the line as

Code:

/dev/sda2   /       ext4   defaults,data=journal   0   1

?
Do I need "defaults" here?

amani · 09-04-2010, 10:58 AM

you should change that with tune2fs

not in fstab

defaults are needed unless you want to change them

see man mount

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salasi · 09-05-2010, 01:05 PM

This is about ext3, but it should clarify your question.